Building A Freestanding Pergola

Freestanding pergolas are built in the same way as a pergola that is connected to a house with some additional support. Freestanding pergolas are completely self supporting with the entire load transferring to the post and then to the concrete footings. However the main problem with freestanding pergolas are not that they carrying extra weight, but in fact the weight wants to move sideways in the wind. The main loads of all freestanding pergolas are the weight of the timber and structure and the wind load. Wind load will depend on where the pergola is built and the area or volume of the pergola.

How to build a freestanding pergola

Step one: Pergola location and set out

Select the location of your freestanding pergola maximum winter sun and block summer sun. Then mark out the site with builder’s string and timber pegs. Make sure that the pergola is square by measuring the diagonals. Dig 300mm x 300mm by 600mm deep and concrete in galvanised post supports or stirrups. Take care to get them exactly right or use the quick and accurate method using props (see how to build a flat roof pergola).

Step two: Install all pergola bearers

Install the four side bearers of your freestanding pergola and bolt into place with galvanised or stainless steel bolts. At the end of step two you should have all posts in place and bearers bolted into position. It is important to clamp or nail on a temporary brace timber on one side and one end of the freestanding pergola. If you do not and you get wind you may end up with a pile of firewood.

Step three: Install corner bracing on all pergola posts

This is where a freestanding pergola will differ from an attached pergola because there is nothing to stop the swaying motion of the wind you must create it. Using pergola span table select the appropriate size of corner bracing for the size of freestanding pergola and the wind rating of your area. If you do not know the wind rating, contact your local council or building authority for advice on area wind rating. I built the pergola in the photos in a very high wind area and it does have corner bracing on it. The photo was take just before the corner bracing was added, before this the whole structure was braced.

Step four: Build your pergola roof structure

From this point on you will need to select a flat roof pergola or a gable roof pergola. Special care must be taken so all timbers are locked together with the correct fixings.

Flat Roof freestanding Pergola

Run your rafters as per your pergola span tables ether on top of the bearers or inside the bearers. If you want to run your rafters inside you will need to use joist hangers or galvanised bulge head screws through the bearers into the rafters. For more on flat roof pergolas.

Gable Roof freestanding Pergola

Install your centre board on temporary supports and work out the cut out and sizing of your rafters and mark and cut one. Then check your one rafter against the pergola sit it on the bearer and the top on the centre board. If correct mark and cut all of your rafters using this as a template. See how to build a gable roof pergola.

Step five: Install your battens

Whether you are building a flat roof or a gable roof freestanding pergola install your battens and nail them off. Then using galvanised bulge head screws screw them all down to the rafters.

Step Six: Finish off your freestanding pergola

To finish check all fixing are tight and that the pergola cannot sway. If you try to shake your freestanding pergola it should not move. Then paint and install and your desired roofing and roof flashing.

Job done! Enjoy.